Louvered fin for heat exchanger

ABSTRACT

A louvered fin for a heat exchanger is disclosed, wherein the louvers include a rib formed thereon to maximize a strength and rigidity thereof and to minimize an amount of material required for production thereof.

FIELD OF THE INVENTION

The invention relates to heat exchangers and more particularly to louvered fins for heat exchangers, wherein a rib is formed on the louvers to maximize a strength and rigidity thereof.

BACKGROUND OF THE INVENTION

An air-cooled fin-type heat exchanger is very well known. Heat exchangers are used for changing the temperature of various working fluids, such as an engine coolant, an engine lubricating oil, an air conditioning refrigerant, and an automatic transmission fluid, for example. The heat exchanger typically includes a plurality of spaced apart fluid conduits or tubes connected between an inlet tank and an outlet tank, and a plurality of heat exchanging fins disposed between adjacent conduits. Air is directed across the fins of the heat exchanger by a cooling fan or a motion of a vehicle, for example. As the air flows across the fins, heat in a fluid flowing through the tubes is conducted through the walls of the tubes, into the fins, and transferred into the air.

One of the primary goals in heat exchanger design is to achieve a high fin column strength. It is known that a greater composite thickness of a fin produces a greater strength of the fin. However, increasing the composite thickness of the fin results in a larger amount of material being used to manufacture the fins. The larger amount of material results in additional weight, which is undesirable. Various types of fin designs have been disclosed in the prior art with the object of increasing the composite thickness to increase the strength of the fin. It would be desirable to produce a louvered fin for a heat exchanger, wherein a strength associated therewith is maximized, and a material usage is minimized.

SUMMARY OF THE INVENTION

Harmonious with the present invention, a louvered fin for a heat exchanger, wherein a strength associated therewith is maximized, and a material usage is minimized, has surprisingly been discovered.

In one embodiment, a heat exchanger fin comprises a base wall having a first end, a second end, and a middle portion; a turnaround louver disposed in the middle portion of the base wall, the turnaround louver having a first edge and a second edge; a plurality of spaced apart entrance louvers disposed between the first end of the base wall and the turnaround louver, the spaced entrance louvers having a first edge and a second edge; a plurality of spaced apart exit louvers disposed between the turnaround louver and the second end of the base wall, the exit louvers having a first edge and a second edge; and at least one rib formed on at least one of the turnaround louver, the entrance louvers, and the exit louvers.

In another embodiment, a heat exchanger fin comprises a base wall having a first end, a second end, and a middle portion; at least one turnaround louver disposed in the middle portion of the base wall, the turnaround louver having a laterally extending first edge, a laterally extending second edge and at least one rib formed between the first edge and the second edge; a plurality of spaced apart entrance louvers disposed between the first end of the base wall and the turnaround louver, the entrance louvers having a laterally extending first edge, a laterally extending second edge, and at least one rib formed between the first edge and the second edge; and a plurality of spaced apart exit louvers disposed between the turnaround louver and the second end of the base wall, the exit louvers having a laterally extending first edge, a laterally extending second edge, and at least one rib formed between the first edge and the second edge.

A method of producing a heat exchanger fin, the method comprises the steps of providing a substantially planar sheet of material; forming a plurality of longitudinally extending ribs in the sheet of material; forming a plurality of laterally extending corrugations in the sheet of material; and forming a plurality of rows of longitudinally extending louvers in the sheet of material, is disclosed.

DESCRIPTION OF THE DRAWINGS

The above, as well as other advantages of the present invention, will become readily apparent to those skilled in the art from the following detailed description of an embodiment of the invention when considered in the light of the accompanying drawings in which:

FIG. 1 is a perspective view of a heat exchanger fin in accordance with an embodiment of the invention;

FIG. 2 is a top sectional view of a plurality of louvers of the heat exchanger fin illustrated in FIG. 1 taken along line 2-2;

FIG. 3 is a perspective view of a heat exchanger fin in accordance with another embodiment of the invention;

FIG. 4 is a top sectional view of a plurality of louvers of the heat exchanger fin illustrated in FIG. 3 taken along a line 4-4;

FIG. 5 is a perspective view of a heat exchanger fin in accordance with another embodiment of the invention;

FIG. 6 is a perspective view of a heat exchanger fin in accordance with another embodiment of the invention;

FIG. 7 is an elevational view of an apparatus used for producing a heat exchanger fin in accordance with an embodiment of the invention; and

FIG. 8 is an elevational view of an apparatus used for producing a heat exchanger fin in accordance with another embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The following detailed description and appended drawings describe and illustrate various exemplary embodiments of the invention. The description and drawings serve to enable one skilled in the art to make and use the invention, and are not intended to limit the scope of the invention in any manner. In respect of the methods disclosed an illustrated, the steps presented are exemplary in nature, and thus, the order of the steps is not necessary or critical.

FIG. 1 shows a heat exchanger fin 10 having an outer surface 11, an inner surface 13, a first end 15 and a second end 17. The heat exchanger fin 10 includes a plurality of base walls 12. It is understood that more or fewer base walls 12 can be used without departing from the spirit or scope of the invention. The base walls 12 have an upper portion 14, a lower portion 16, a first end 18, a second end 20, and a middle portion 22. The middle portion 22 is disposed intermediate the first end 16 and the second end 18.

The base walls 12 include a leading edge louver 23, a plurality of entrance louvers 24, a turnaround louver 26, a plurality of exit louvers 28, and a trailing edge louver 29. The leading edge louver 23 and entrance louvers 24 are connected to the upper portion 14 of the base wall 12 at a first end 30 and to the lower portion 16 of the base wall 12 at a second end 32. As more clearly shown in FIG. 2, the leading edge louver 23 and each of the entrance louvers 24 includes a first surface 33, a second surface 35, a first edge 34, a spaced apart second edge 36, and a rib 38. The rib 38 is formed between the first edge 34 and the second edge 36 and extends laterally outwardly from the second surface 35. A single rib 38 is shown formed on the leading edge louver 23 and each entrance louver 24. However, it is understood that more or fewer ribs 38 can be formed on the leading edge louver 23 and the entrance louvers 24 as desired without departing from the scope of the invention. In the embodiment shown, the ribs 38 extend from the first end 30 to the second end 32 of the leading edge louver 23 and entrance louvers 24. A gap 39 is formed between adjacent entrance louvers 23, 24 and between the turnaround louver 26 and the entrance louver 24 adjacent the turnaround louver 26.

The turnaround louver 26 is connected to the upper portion 14 of the base wall 12 at a first end 40 and to the lower portion 16 of the base wall 12 at a second end 42. As illustrated in FIG. 2, the turnaround louver 26 includes a first surface 43, a second surface 45, a first edge 44, a spaced apart second edge 46, and a rib 48. The rib 48 is formed between the first edge 44 and the second edge 46 and extends laterally outwardly from the second surface 45. A single rib 48 is shown formed on the turnaround louver 26. However, it is understood that more or fewer ribs 48 can be formed on the turnaround louver 26 as desired. The rib 48 extends from the first end 40 to the second end 42 of the turnaround louver 26.

The exit louvers 28 and the trailing edge louver 29 are connected to the upper portion 14 of the base wall 12 at a first end 50 and to the lower portion 16 of the base wall 12 at a second end 52. As shown in FIG. 2, each of the exit louvers 28 and the trailing edge louver 29 includes a first surface 53, a second surface 55, a first edge 54, a spaced apart second edge 56, and a rib 58. The rib 58 is formed between the first edge 54 and the second edge 56 and extends laterally outwardly from the second surface 55. A single rib 58 is shown formed on each exit louver 28 and the trailing edge louver 29. However, it is understood that more or fewer ribs 58 can be formed on the exit louvers 28 and the trailing edge louver 29 as desired. The ribs 58 extend from the first end 50 to the second end 52 of the exit louvers 28 and the trailing edge louver 29. A gap 59 is formed between adjacent louvers 28, 29 and between the turnaround louver 26 and the exit louver 28 adjacent the turnaround louver 26.

As is known in the art, air is caused to flow through the gaps 39 between adjacent entrance louvers 24. Heat removed from a fluid (not shown) flowing in flow tubes (not shown) is transferred through the heat exchanger fin 10 and the entrance louvers 24 to the air. The air is then caused to change direction at the turnaround louver 26. The air flows through the gaps 59 between adjacent exit louvers 28 where additional heat is transferred from the exit louvers 28 to the air.

A composite thickness of the louvers 24, 26, 28 is increased as a result of the formation of the ribs 38, 48, 58 on the louvers 24, 26, 28. The increase in the composite thickness of the louvers 24, 26, 28 results in an increased strength of the fin 10. For the embodiment shown in FIGS. 1 and 2, an increase in strength of about 18% has been measured.

An increased strength of the fin 10 allows for the use of a thinner gauged flat stock of material to make the fin 10. Accordingly, a fin 10 having a strength substantially the same as fin structures of the prior art can be made with less material. Thus, overall weight of the fin 10 is minimized. It has been shown that a fin 10 including louvers 24, 26, 28 having ribs 38, 48, 58 formed thereon can be made with up to 20% less material than fin structures of the prior art.

The heat exchanger fin 10 shown in FIGS. 3 and 4 includes ribs 381, 48′, 58′. Similar structure to that described above for FIGS. 1 and 2 repeated herein with respect to FIGS. 3 and 4 includes the same reference numeral and a prime (′) symbol. The ribs 38′, 48′, 58′ are formed to extend laterally outwardly from respective first surfaces 33, 43, 53. The remaining structure is the same as discussed above for FIGS. 1 and 2. Air flow through the louvers 24′, 26′, 28′ is the same as described above for FIGS. 1 and 2.

FIG. 5 shows a strong heat exchanger fin in accordance with another embodiment of the invention. Similar structure to that described above for FIGS. 1 and 2 repeated herein with respect to FIG. 5 includes the same reference numeral and a double prime (″) symbol. In this embodiment, the ribs 38″, 48″, 58″ extend from the first end 15 of the fin 10″ to the second end 17 of the fin 10″. The ribs 38″, 48″, 58″ may be formed to extend laterally outwardly from the inner surface 13 of the fin 10″ as shown in FIG. 5. The ribs 38′″, 48′″, 58′″ may also be formed to extend laterally outwardly from the outer surface 11 of the fin 10″ as shown in FIG. 6. Similar structure to that described above for FIGS. 1 and 2 repeated herein with respect to FIG. 6 includes the same reference numeral and a triple prime (′″) symbol. The remaining structure and air flow through the louvers 24″, 26″, 28″, 24′″, 26′″, 28′″ is the same as described above for FIGS. 1 and 2.

A method of forming the heat exchanger fin 10 described in FIGS. 1-2 will now be described. A substantially planar sheet of material 110 is provided, such as aluminum, for example. As shown in FIG. 7, the sheet of material 110 is fed into a retention roll 111 for height and straightness adjustments and then into a set of rib forming rolls 112. A first one of the rib forming rolls 112 includes of a plurality of spaced annular protuberances (not shown). A second one of the rib forming rolls 112 includes a plurality of spaced apart annular channels or indentations. The protuberances and indentations of the rib forming rolls 112 cooperate to form a plurality of continuous ribs 38, 48, 58 in the sheet of material 110. Optionally, the sheet of material 110 can then be fed into a second retention roll 111, as illustrated in FIG. 8. Thereafter, the sheet 110 is fed into a set of corrugation fin forming rolls 114. Cutters (not shown) disposed on the corrugation fin forming rolls 114 cut the sheet 110 to form a plurality of rows. Each of the rows includes a leading edge louver 23, a plurality of entrance louvers 24, a turnaround louver 26, a plurality of exit louvers 28, and a trailing edge louver 29. The corrugation fin forming rolls 114 simultaneously alternately bend the sheet 110 to form corrugations and give the sheet 110 a wave-like shape. The corrugation fin forming rolls 114 also cooperate to flatten the sheet 110 between adjacent rows of louvers 23, 24, 26, 28, 29. Thus, the ribs 38, 48, 58 formed on the top portion 14 and the bottom portion 16 of the sheet 110 are removed. The sheet 110 is fed into a density station 116 where further adjustments to the sheet 110 can be accomplished as desired. The sheet 110 is fed into a cutoff station 118 where the sheet 110 is cut to a desired length.

To form the fin 10″ described in FIG. 5 above, a flattening of the sheet 110 between adjacent rows of louvers 23″, 24″, 26″, 28″, 29″ is eliminated from the process described. The ribs 38″, 48″, 58″ produced by this method extend continuously from the first end 15 of the fin 10 to the second end 17 of the fin 10, rather than terminating at the first ends 30, 40, 50 and the second ends 32, 42, 52 of the louvers 24″, 26″, 28″.

From the foregoing description, one ordinarily skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications to the invention to adapt it to various usages and conditions. 

1. A heat exchanger fin comprising: a base wall having a first end, a second end, and a middle portion; a turnaround louver disposed in the middle portion of said base wall, said turnaround louver having a first edge and a second edge; a plurality of spaced apart entrance louvers disposed between the first end of said base wall and said turnaround louver, said spaced entrance louvers having a first edge and a second edge; a plurality of spaced apart exit louvers disposed between said turnaround louver and the second end of said base wall, said exit louvers having a first edge and a second edge; and at least one rib formed on at least one of said turnaround louver, said entrance louvers, and said exit louvers.
 2. The fin according to claim 1, wherein said rib is formed between the first edge and the second edge of the at least one of said turnaround louver, said entrance louvers, and said exit louvers.
 3. The fin according to claim 2, wherein said rib is formed substantially parallel to the first edge and the second edge of at least one of said turnaround louver, said entrance louvers, and said exit louvers.
 4. The fin according to claim 1, wherein said rib is formed from a first end to a second end of the at least one of said turnaround louver, said entrance louvers, and said exit louvers.
 5. The fin according to claim 1, wherein said rib is formed to extend laterally outwardly from one of a first surface and a second surface of the at least one of said turnaround louver, said entrance louvers, and said exit louvers.
 6. The fin according to claim 1, further comprising a leading edge louver and a trailing edge louver, the leading edge louver disposed between the first end of said base wall and said entrance louvers, and having a first edge, a second edge, and a rib formed thereon, the trailing edge louver disposed between said exit louvers and the second end of said base wall and having a first edge, a second edge, and a rib formed thereon.
 7. A heat exchanger fin comprising: a base wall having a first end, a second end, and a middle portion; at least one turnaround louver disposed in the middle portion of said base wall, said turnaround louver having a laterally extending first edge, a laterally extending second edge, and at least one rib formed between the first edge and the second edge; a plurality of spaced apart entrance louvers disposed between the first end of said base wall and said turnaround louver, said entrance louvers having a laterally extending first edge, a laterally extending second edge, and at least one rib formed between the first edge and the second edge; and a plurality of spaced apart exit louvers disposed between said turnaround louver and the second end of said base wall, said exit louvers having a laterally extending first edge, a laterally extending second edge, and at least one rib formed between the first edge and the second edge.
 8. The fin according to claim 7, wherein the ribs formed on said turnaround louver, said entrance louvers, and said exit louvers are formed to extend laterally outwardly from one of a first surface and a second surface of said turnaround louver, said entrance louvers, and said exit louvers.
 9. The fin according to claim 7, further comprising a leading edge louver and a trailing edge louver, the leading edge louver disposed between the first end of said base wall and said entrance louvers, and having a laterally extending first edge, a laterally extending second edge, and a rib formed thereon, the trailing edge louver disposed between said exit louvers and the second end of said base wall and having a laterally extending first edge, a laterally extending second edge, and a rib formed thereon.
 10. The fin according to claim 7, wherein the ribs extend from a first end to a second end of the fin on said base wall.
 11. The fin according to claim 10, wherein the ribs extend laterally outwardly from one of an inner surface and an outer surface of the fin.
 12. The fin according to claim 7, wherein the ribs of said entrance louvers are substantially parallel to the first edge and the second edge thereof.
 13. The fin according to claim 7, wherein the ribs of said exit louvers are substantially parallel to the first edge and the second edge thereof.
 14. A method of producing a heat exchanger fin, the method comprising the steps of: providing a substantially planar sheet of material; forming a plurality of longitudinally extending ribs in the sheet of material; forming a plurality of laterally extending corrugations in the sheet of material; and forming a plurality of rows of longitudinally extending louvers in the sheet of material.
 15. The method according to claim 14, wherein the ribs formed in the sheet of material are continuous.
 16. The method according to claim 15, further comprising the steps of providing a set of rib forming rolls and a set of corrugations forming rolls to respectively form the ribs and corrugations in the sheet of material.
 17. The method according to claim 16, further comprising the step of flattening the sheet of material between adjacent rows of louvers.
 18. The method according to claim 17, wherein the second set of rolls is used to flatten the sheet of material between adjacent rows of louvers.
 19. The method according to claim 18, further comprising the step of providing a density station to further process the sheet of material.
 20. The method according to claim 19, further comprising the step of providing a cutoff station for cutting the fin to a desired length. 